C100, F3, or FS700?

I'm in the market for a new camera but am having a horrible time figuring out which way to go with it. For my background, I've owned a 5D MKiii since it came out and while I like the camera, I'm pretty tired of the DSLR ergonomics and soft image. Most of my work is as a DP/operator (out of necessity, not choice) for web videos and indie films. The cameras I'm looking at now (along with the pros and cons for them I can think of) are:

C100:
Pros: It's cheap enough that I can hold on to my 5D as a stills/B cam/slow motion cam. It has a great image, and will fit really well into my setup as I mostly have EF mount lenses and I would not need to upgrade my tripod to support it.

Cons: It's the most feature deprived out of all the options. No slow motion, but I would keep my 5D around for that.

F3:
Pros: gorgeous image, high latitude, will probably result in the best final image.

Cons: probably the most expensive upgrade as I would need new media, batteries, and a lens adapter, possibly an external recorder as well.

FS700:
Pros: Lots of features for the price

Cons: ergonomics, I don't really know much about how the camera performs, although I've heard quite a few people ragging on the image quality.

Any thoughts? The C100 feels like the next logical step for me, but I really WANT to be shooting with the F3, does the "dress for the job you want" mantra apply with cameras?

I'm going to jump out of your list of three a bit (although every similar to it) and suggest the Canon C300.

Since we began shooting with it a few months ago it has quickly become just about my favorite camera every.

It will have the ergonomics you like from the C100, is only a couple of bucks more (literally) than the F3, overcranks for slow-mo, shoots on inexpensive media, will take your existing EF lenses (well, the EF version will, not the PL version, obviously), has dozens of very useful features, great viewfinder with redline focusing that works like a charm... and above all that has a picture that will absolutely knock your socks off.

I would love the C300 and if the price weren't an issue (I'd only be getting an F3 if I could get a great deal on it, $7k max) this wouldn't even be a question. I'm told that the C300 is a very hot camera for rentals, but how do you get established as someone who rents out their camera? Do I just send out an email to all of the local production companies and wait for people to start throwing money at me? In a market like Austin, can I expect to be able to pay for my lease with rentals?

[Jensen Yancey]"I'd only be getting an F3 if I could get a great deal on it, $7k max"

Wow... where?? An F3 body generally goes for exactly twice that... right at $14K. That's almost exactly the same price as the C300. That's why I suggested it, if an F3 is in the budget, then the C300 is right at the same dollar mark. I've never heard of or seen an F3 for anywhere near the numbers you mentioned.

As for renting your gear out? That's usually a nightmare (especially for cameras or any delicate things), best left to the people who specialize in just renting gear for a living (and have in-house maintenance departments and engineers that can keep things fixed and tweaked perfectly). We never ever rent out gear (even if our insurance would allow it, which it doesn't)... if you want our gear it comes with a crew. The one and only time I ever rented out anything it was something that was fairly indestructible (a jib) and it was rented to someone I knew who I thought knew what they were doing. It definitely came back in poorer condition than it went out.

I just picked up the C100, had the same concerns as you did, kept my 7D &60D and made an "upgrade" that made financial and technical sense. For what I do, the C100 is fine, the "viewfinder issues" are not as bad as some people made them out to be, so I am happy for that. I did buy a Zacuto replacement eyecup and foam cover, they work great, "almost" made for the viewfinder. I considered the FS100 &700, but needed a camera that was more hand holdable than the Sonys. For the price, the C100 was it.

I have a similar dilemma. I'm looking at the C100, FS700 and the upcoming Blackmagic Cinema Camera 4K. The beauty of the C100 and the BCC 4K is that they're both internally compatible with my Canon glass.
C100 is the only one that isn't 4K capable, not that 4K is an issue for me right now. But it's a nice future proof feature. I prefer the look of the footage straight out of the C100 better than the FS700. The BCC 4K is a dark horse in this area but, judging from their previous camera it should produce a very nice image as well.